string.md

Strings

• When you store a string in memory, the number of bytes used = 1*n+1 where n represents the number of characters and the 1 comes from \0 added by C in strings.

#include <stdio.h>

int main(void)
{
    char c1 = 'H';
    char c2 = 'I';
    char c3 = '!';

    printf("%c%c%c\n",c1,c2,c3);
}

Showing ASCII:

#include <stdio.h>

int main(void)
{
    char c1 = 'H';
    char c2 = 'I';
    char c3 = '!';

    printf("%i %i %i\n",c1,c2,c3);
}

#include <cs50.h>
#include <stdio.h>

int main(void)
{
    string s = "HI!";
    printf("%s\n",s);
}

#include <cs50.h>
#include <stdio.h>

int main(void)
{
    string s = "HI!";
    printf("%c%c%c\n",s[0],s[1],s[2]);
}

Showing ASCII with the last NUL value:

#include <cs50.h>
#include <stdio.h>

int main(void)
{
    string s = "HI!";
    printf("%i %i %i %i\n",s[0],s[1],s[2],s[3]);
}

Manually,

#include <cs50.h>
#include <stdio.h>

int main(void)
{
    string words[2];
    words[0]="HI!";
    words[1]="BYE!";

    printf("%c%c%c\n",words[0][0],words[0][1],words[0][2]);
    printf("%c%c%c%c\n",words[1][0],words[1][1],words[1][2],words[1][3]);

}

Mine:

#include <cs50.h>
#include <stdio.h>

int main(void)
{
    string words[2];
    words[0]="HI!";
    words[1]="BYE!";

    for(int i=0;i<2;i++)
    {
        for(int j=0;j<4;j++)
        {
            printf("%c",words[i][j]);
        }
        printf("\n");
    }
}

Finding length of string:

#include<cs50.h>
#include<stdio.h>

int main(void)
{

    string name = get_string("What's your name? ");

    int n = 0;
    
    while (name[n]!='\0')
    {
        n++;
    }
    printf("%i\n",n);
}

This can be achieved by using the <string.h>

#include<string.h>
#include<cs50.h>
#include<stdio.h>

int main(void)
{
    string name = get_string("What's your name? ");
    int n = strlen(name);

    printf("%i\n",n);
}

Converting lowercase to uppercase:

#include<cs50.h>
#include<stdio.h>
#include<string.h>

int main(void)
{
    string s = get_string("Before: ");
    printf("After: ");
    for (int i = 0; i < strlen(s);i++)
    {
        if(s[i]>='a'&&s[i]<='z')
        {
            s[i]-=32;
            printf("%c",s[i]);
        }
        else
        {
            printf("%c",s[i]);
        }
    }
    printf("\n");
}

Another method using ctype.h

#include<cs50.h>
#include<stdio.h>
#include<string.h>
#include <ctype.h>

int main(void)
{
    string s = get_string("Before: ");
    printf("After: ");
    for (int i = 0, n = strlen(s); i < n;i++)
    {
        printf("%c",toupper(s[i]));
    }
    printf("\n");
}