Bunny Eat Broccoli Repetition – Simple loops and Conditional loops
Repetition and while loops. Assignments Due – Lab 4.
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Repetition and while loops
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Transcript of Repetition and while loops. Assignments Due – Lab 4.
Repetition and while loops
Assignments
• Due – Lab 4
Examples
• Where is repetition necessary – List a set of problems
Types of Loops
• Counting loop– Know how many times to loop
• Sentinel-controlled loop– Expect specific input value to end loop
• Endfile-controlled loop– End of data file is end of loop
• Input validation loop– Valid input ends loop
• General conditional loop– Repeat until condition is met
while
while(condition)
{
statements
}
while
int i = 0; //initialization of control variable
while(i < end_value) //condition
{
printf(“%d\n”, i);
i++; //update – DO NOT FORGET THIS!
}
for
int i;
for(i = 0; i < end_value; i++)
{
printf(“%d\n”, i);
}
Sentinel-controlled
int input;
printf(“enter number – 0 to quit: “);scanf(“%d”, &input);while(input != 0) {
printf(“your number is %d”, input);printf(“enter number – 0 to quit: “);scanf(“%d”, &input);
}
Input Validation
int input;
printf(“enter number – 0 to 100: “);scanf(“%d”, &input);while(input < 0 || input > 100) {
printf(“enter number – 0 to quit: “);scanf(“%d”, &input);
}
do-while
int input;
do
{
printf(“enter number – 0 to quit: “);
scanf(“%d”, &input);
} while(input < 0 || input > 100);
Infinite Loops
• If your program “hangs” – you probably forgot to update your control variable
• Why is this bad?
for(i = 0; i != end_value; i++) //BAD
Infinite Loops
• If your program “hangs” – you probably forgot to update your control variable
• Why is this bad?for(i = 0; i != end_value; i++) //BAD{
printf(“Hello”);i *=5;
}
for(i = 0; i < end_value; i++) //BETTER
