# C Program to compute the difference between two dates.

Write a C program to compute the difference between two dates.In this C Program, We check the date is valid or not and then calculating the No. of days of first date and second date from Jan 1 of first date, then subtract the smaller date from another. Read more about C Programming Language .

`/************************************************************ You can use all the programs on  www.c-program-example.com* for personal and learning purposes. For permissions to use the* programs for commercial purposes,* contact [email protected]* To find more C programs, do visit www.c-program-example.com* and browse!* *                      Happy Coding***********************************************************/#include<stdio.h>#include<math.h>#include<conio.h>void main(){    int day1,mon1,year1,day2,mon2,year2;    int ref,dd1,dd2,i;    clrscr();    printf("Enter first date  day, month, yearn");    scanf("%d%d%d",&day1,&mon1,&year1);    printf("Enter second date day, month, yearn");    scanf("%d%d%d",&day2,&mon2,&year2);    ref = year1;    if(year2<year1)    ref = year2;    dd1=0;    dd1=dater(mon1);    for(i=ref;i<year1;i++)    {        if(i%4==0)        dd1+=1;    }    dd1=dd1+day1+(year1-ref)*365;    dd2=0;    for(i=ref;i<year2;i++)    {        if(i%4==0)        dd2+=1;    }    dd2=dater(mon2)+dd2+day2+((year2-ref)*365);    printf("nn Difference between the two dates is %d days",abs(dd2-dd1));        getch();}int dater(x){ int y=0;    switch(x)    {        case 1: y=0; break;        case 2: y=31; break;        case 3: y=59; break;        case 4: y=90; break;        case 5: y=120;break;        case 6: y=151; break;        case 7: y=181; break;        case 8: y=212; break;        case 9: y=243; break;        case 10:y=273; break;        case 11:y=304; break;        case 12:y=334; break;        default: printf("Invalid Inputnnnn"); exit(1);    }    return(y);}`
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