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About usModule 9: Array processing and Table handling
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Difference between Subscript and Index
| Subscript | Index |
|---|---|
| Denotes position/occurrence of the element in an array | Denotes displacement of the element from beginning of an array |
| Declared in WORKING-STORAGE SECTION separately | No need to declare in WORKING-STORAGE SECTION |
| Occurrence is converted into displacement to access array element thus, slower. | Since it already denotes displacement, thus no conversion needed. This makes it faster and efficient |
| It is valid to use subscript in arithmetic operation or for display | It is invalid to use INDEX in arithmetic operation or for display |
| Subscript modification is possible with any arithmetic operation | INDEX modification is possible only with SET, SEARCH and PERFORM |