How do you return to a main function?

Answer 1

..use do{} while{}..

for example..

#include
main(){
int choose;
double a,b,c;
printf("Enter 7 if you want to use the calculator. Otherwise,type any character.\n");
scanf("%d",&choose);
do{
if (choose==7){
printf("Press 1 for addition.\n");
printf("Press 2 for subtraction.\n");
printf("Press 3 for multiplication.\n");
printf("Press 4 for division.\n");
scanf("%d",&choose);
if (choose==1){
printf("Enter the addends\n");
scanf("%lf %lf", &a,&b);
c=a+b,
printf("The sum of %lf and %lf is %lf.\n",a,b,c);
}else if(choose==2){
printf("Enter the minuend and subtrahend\n");
scanf("%lf %lf", &a,&b);
c=a-b,
printf("The difference of %lf and %lf is %lf.\n",a,b,c);
}else if(choose==3){
printf("Enter the multipliers\n");
scanf("%lf %lf", &a,&b);
c=a*b,
printf("The product of %lf and %lf is %lf.\n",a,b,c);
}else if(choose==4){
printf("Enter the dividend and divisor\n");
scanf("%lf %lf", &a,&b);
c=a/b,
printf("The quotient of %lf and %lf is %lf.\n",a,b,c);
}else{
printf("You have entered an invalid digit.\n");}
printf("If you want to continue,press 7 and choose again from 1 to 4.\n");
printf("Do you want to exit? Enter any key.\n");
scanf("%d",&choose);
}
}while(choose==7);
}