.
./arithmetic.c
./arrays.c
./array_walk.c
./cargs.c
./charbychar.c
./datatypes_and_print.c
./datatypes.c
./dynmem.c
./hello.c
./index.html
./sizeof.c
./strcmp_example.c
./string.c
./strings.c
./strlen_example.c

. 1/16

./arithmetic.c 2/16

/* A review of the basic arithmetic operators in C. */

#include <stdio.h>

int main() {
    int x,y;
    int r1,r2,r3,r4,r5;
    double d1;
    
    x=4;
    y=7;
    r1=x+y;
    r2=x-y;
    r3=x/y;
    d1 = 1/2;
    r4=x*y;
    printf("r1 r2 r3 r4: %d %d %d %d\n",r1,r2,r3,r4);
    printf("d1: %f\n", r3, d1);
    r3++;
    r4--;
    r5=r4%r1;
    printf("r3 r4 r5: %d %d %d\n",r3,r4,r5);
    
    // WARNING: 
    // If your data is an integer and you format it as 
    // a float, chaos will ensue.
    printf("%f %f %f\n", 1 / 2, 1.0 / 2, 3.4/2);
}

./arrays.c 3/16

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/* A review of arrays in C.  */

#include <stdio.h>

int main() {
    int a[3];
	int b[2];
	
	a[0] = 1;
	a[1] = -1;
	a[2] = 2;
	b[0] = 4;
	
	printf("%d %d %d\n", a[0], a[1], a[2]);
	
	printf("%d\n", a[4]);
	
	printf("%d\n", b[1]); // some compilers zero out the memory; others don't.
}

./array_walk.c 4/16

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#include <stdio.h>
 
int main() {
    int iarray[100];
    int n, num, status, sum, i;
    int* iptr;
    
    iptr = iarray;
    n=0;
    
    while( n < 100 ) {
        // scanf returns the total number of bytes read
        status = scanf("%d", &num);
        if( status == 0 || num == 0 ) {
            break;
        }
        *iptr++ = num;
        n++;
    }
    
    for( iptr = iarray, sum=0; n > 0; n--) {
        sum += *iptr++;
    }
    
    printf("sum = %d\n", sum);
}

./cargs.c 5/16

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/* Print out the command line arguments 
 * - they are an array of strings 
 */

#include <stdio.h>
#include <string.h>

int main(int argc, char *argv[]) {
	int i, j;

	for (i = 0; i < argc; i++) {
		j = 0;
		while (argv[i][j] != '\0') {
			printf("%c", argv[i][j]);
			j++;
		}
		printf("\n");
	}

	for (i = 0; i < argc; i++)
		printf("%s\n", argv[i]);
}

./charbychar.c 6/16

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/* What does this code do? */

#include <stdio.h>
#include <string.h>

int main() {
	int i, j;
	char s[6];

	s[0] = 'a';
	s[1] = 'b';
	s[2] = 'a';
	s[3] = 'c';
	s[4] = '\0';
	printf("%s\n", s);
	i = 0;
	j = 0;
	while (s[i] != '\0') {
		if (s[i] != 'a') {
			s[j] = s[i];
			j++;
		}
		i++;
	}
	s[j] = '\0';
	printf("%s\n", s);
}

./datatypes_and_print.c 7/16

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/*
 * A review of the basic data types in C.
 */

#include <stdio.h>

int main() {
	int x, y;
	char a;
	float f, e;
	double d;

	x = 4;
	y = 7;
	a = 'H';
	f = -3.4;
	d = 54.123456789;
	e = 54.123456789;

	printf("%d %c %f %lf\n", x, a, e, d);
	printf("%d %c %.9f %.3lf\n", x, a, e, d);
}

./datatypes.c 8/16

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/* A review of the basic data types in C. */

#include <stdio.h>

int main() {
    int     x,y;
    char    a;
    float   f,e;
    double  d;
    
    x=4;
    y=7;
    a='H';
    f=-3.4;
    d=54.123456789;
    e=54.123456789;
    
    printf("%d %c %f %lf\n",x,a,e,d);
    printf("%d %c %.9f %.9lf\n",x,a,e,d);
}

./dynmem.c 9/16

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/* A review of the basic arithmetic operators in C.  */

#include <stdio.h>
#include <stdlib.h>

int main() {
	int* iptr = malloc(sizeof(int)); 
	
	*iptr = 6;
	
	printf("%d\n", *iptr);
}

./hello.c 10/16

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#include <stdio.h>

main() {
    printf("Hello World, and Goodbye!\n");
}

./index.html 11/16

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<html>
<head><title>Examples for /home/faculty/sprenkle/public_html/cs330/examples/03-c</title>
<link rel="stylesheet" type="text/css" href="http://www.cs.wlu.edu/~sprenkle/cs330/css/themes/spacelab.min.css" />
<link rel="stylesheet" type="text/css" href="http://www.cs.wlu.edu/~sprenkle/cs330/css/course.css" />
<link rel="stylesheet" type="text/css" href="http://www.cs.wlu.edu/~sprenkle/cs330/css/syntax.css" />
<link rel="stylesheet" type="text/css" href="http://www.cs.wlu.edu/~sprenkle/cs330/css/style.css" />
</head>
<body>
<h1>Examples for /home/faculty/sprenkle/public_html/cs330/examples/03-c</h1>
<ul>
<li><a href=".//code.html">All IN ONE FILE (pretty syntax)</a>
<li><a href=".//arithmetic.c">arithmetic.c</a></li>
<li><a href=".//array_walk.c">array_walk.c</a></li>
<li><a href=".//arrays.c">arrays.c</a></li>
<li><a href=".//cargs.c">cargs.c</a></li>
<li><a href=".//charbychar.c">charbychar.c</a></li>
<li><a href=".//datatypes.c">datatypes.c</a></li>
<li><a href=".//datatypes_and_print.c">datatypes_and_print.c</a></li>
<li><a href=".//dynmem.c">dynmem.c</a></li>
<li><a href=".//hello.c">hello.c</a></li>
<li><a href=".//sizeof.c">sizeof.c</a></li>
<li><a href=".//strcmp_example.c">strcmp_example.c</a></li>
<li><a href=".//string.c">string.c</a></li>
<li><a href=".//strings.c">strings.c</a></li>
<li><a href=".//strlen_example.c">strlen_example.c</a></li>
</ul>
</body>

./sizeof.c 12/16

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#include <stdio.h>

int function(int x[]) {
    return sizeof(x);   
}

int main() {
   int a[20];
   printf("sizeof(int) = %d; sizeof(a) = %d\n", sizeof(int), sizeof(a));
	printf("function returns %d\n", function(a));
}

./strcmp_example.c 13/16

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#include <stdio.h>
#include <string.h>

int main()
{
    char str1[] = "abcd";
    char str2[] = "abCd";
    char str3[] = "abcd";
    int result;

    // comparing strings str1 and str2
    result = strcmp(str1, str2);
    printf("strcmp(str1, str2) = %d\n", result);
    printf("!strcmp(str1, str2) = %d\n", !result);


    // comparing strings str1 and str3
    result = strcmp(str1, str3);
    printf("strcmp(str1, str3) = %d\n", result);
    printf("!strcmp(str1, str3) = %d\n", !result);


    return 0;
}

./string.c 14/16

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/* A close look at a character array.
   Run program multiple times, after running different programs.
*/

#include <stdio.h>
#include <string.h>

int main() {
	char s[6];
	int i;
	
	printf("in the beginning, s is %s\n", s);
	
	/* stresses the importance of making the end of the string explicit.
	What does the data in the array look like to start? */
	for( i = 0; i < 6; i++ ) {
	    printf("%c\n", s[i]);
	}

	s[0] = 'a';
	s[1] = 'b';
	
	printf("at the end, s is %s\n", s);
	
}

./strings.c 15/16

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/*
 * Removes the 'a's from a string
 */

#include <stdio.h>
#include <string.h>

main() {
	int i, j;
	char s[6];

	s[0] = 'a';
	s[1] = 'b';
	s[2] = 'a';
	s[3] = 'c';
	s[4] = 1;
	
	i = 0;
	j = 0;
	while (s[i] != 0) {
		if (s[i] != 'a') {
			s[j] = s[i];
			j++;
		}
		i++;
	}
	s[j] = 0;  // alternatively, s[j] = '\0'; character has value 0
	printf("%s\n", s);
}

./strlen_example.c 16/16

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#include <stdio.h>
#include <string.h>
int main() {
    char a[20]="Program";
    char b[20]={'P','r','o','g','r','a','m','\0'};
    char c[20];
    int i;

    printf("Enter a string: ");
    fgets(c, 20, stdin);

    printf("Length of string a = %d \n", strlen(a));

    //calculates the length of string before null charcter.
    printf("Length of string b = %d \n", strlen(b));
    
    // why is the length one longer than you'd expect?
    printf("Length of string c = %d \n", strlen(c));
    
    i=0;
    while( c[i] != '\0' ) {
        printf("%i: %c\n", i, c[i]);   
        i++;
    }

    return 0;
}

Generated by GNU Enscript 1.6.6.

Contents

. 1/16

./arithmetic.c 2/16

./arrays.c 3/16

./array_walk.c 4/16

./cargs.c 5/16

./charbychar.c 6/16

./datatypes_and_print.c 7/16

./datatypes.c 8/16

./dynmem.c 9/16

./hello.c 10/16

./index.html 11/16

./sizeof.c 12/16

./strcmp_example.c 13/16

./string.c 14/16

./strings.c 15/16

./strlen_example.c 16/16